A power distribution architecture, called a “Factorized Power Architecture” (“FPA”), is described in Vinciarelli, “Factorized Power Architecture,” U.S. patent application Ser. No. 10/264,327, filed Oct. 1, 2002 (the “Factorized Application”), assigned to the same assignee as this application and incorporated here by reference. In general, the power density, efficiency, and flexibility of a point-of-load power converter, and the power-sharing performance of paralleled arrays of such converters, may be improved by factorizing away the power conversion functions associated with voltage regulation and by providing only essential functions at the point-of-load, such as voltage transformation and/or isolation.
One example of a FPA, system 20, is shown in FIG. 1. An upstream power regulator module (“PRM”) 21, at a first location accepts power from an input source 22 and converts it into a controlled bus voltage at its output, Vf, which is distributed over a distance via a “factorized” distribution bus 23 to a remotely located Voltage Transformation Module (“VTM”) 24. The VTM includes an isolation transformer (not shown) and transforms the voltage Vf into a voltage Vout, for delivery to a load 25. The VTM 24 delivers a DC output voltage, Vout, which, for a certain load current, is essentially a fixed fraction of the voltage, Vin (nominally Vf) delivered to its input.
The voltage transformation ratio or voltage gain of the VTM (which may be defined as the ratio, K=Vout/Vin, of its output voltage to its input voltage at a load current) is fixed by design, e.g. by the VTM converter topology, its timing architecture and the turns ratio of the transformer included within it. The sine amplitude converter (“SAC”) disclosed in the Factorized Application is preferred for its high performance characteristics, including a low effective output resistance and elimination of inductive and capacitive impedances in the series output impedance. The effective output resistance or output impedance, as the case may be, of a VTM will cause some “droop” in output voltage as a function of load current without some form of compensation.
Modem electronic systems such as telecommunications systems and computer systems require power to be supplied at several different voltages and oftentimes require the controlled sequencing of the voltages while powering up and powering down the system. Referring for example to FIG. 2, a prior art distributed power architecture (“DPA”) system 30 is shown with a power source 31 supplying power to a front end 32. The front end conditions the power and delivers a nominal DC bus voltage VBUS to a plurality of DC-DC converters 34A–34C that provide isolation, voltage transformation, and output regulation, deliver power at regulated voltages VLA–VLC to respective loads 25A–25C. A controller 33 provides signals 36A–36C to enable or disable respective converters 34A–34C providing the necessary sequencing of output voltages. Many commercially available DC-DC converters include an enable/disable pin with which a controller e.g., controller 33 could be interfaced to properly control the timing and sequence of the power sources throughout the system. For example, Vicor, 25 Frontage Road, Andover, Mass. 01810 offers first and second generation DC-DC converters having Gate-In and Primary-Control (“PC”) terminals, respectively, that may be used for enabling and disabling the power converters.